The title of this post isn't a typo—its purpose is to ask how we can effectively do fundraising and movement-building for the effective altruism movement. This is an important question, because the return on these activities is potentially very high. As Robert Wiblin wrote on the topic of fundraising over a year ago:

GiveWell’s charity recommendations – currently Against Malaria Foundation, GiveDirectly and the Schistosomiasis Control Initiative – are generally regarded as the most reliable in their field. I imagine many readers here donate to these charities. This makes it all the more surprising that it should be pretty easy to start a charity more effective than any of them.

All you would need to do is found an organisation that fundraises for whoever GiveWell recommends, and raises more than a dollar with each dollar it receives. Is this hard? Probably not. As a general rule, a dollar spent on fundraising seems to raise at least several dollars.

Similarly, a more recent post at the 80,000 Hours blog asked "What cause is most effective?" and ended up concluding that "promoting effective altruism" was tied with "prioritization research" for the currently most effective cause. According to 80,000 Hours:

Promoting effective altruism is effective because it’s a flexible multiplier on the next most high-priority cause. It’s important because we expect the most high-priority areas to change a great deal, so it’s good to build up general capabilities to take the best opportunities as they are discovered. Moreover, in the recent past, investing in promoting effective altruism has resulted in significantly more resources being invested in the most high-priority areas, than investing in them directly. For instance, for every US$1 invested in GiveWell and Giving What We Can, more than $7 have been moved to high-priority interventions.

However, there are a number of questions to ask about this: for example, can we trust 80,000 Hours' estimates of the multiplier on giving to Give Well and GWWC? Might other organizations (such as the Centre for Effective Altruism, which is behind 80,000 Hours) be more effective at movement-building?

One interesting question is whether, from a movement-building perspective, it might make sense to (1) donate to an organization that both does movement building / cause-prioritization as well as making grants to object-level useful things (as GiveWell does) or (2) split your donation between an organization that does movement building and an organization that does object-level useful things. The rationale for this, particularly (2), is that donating exclusively to movement-building might not be the best thing for movement building, for a number of reasons:

Donating exclusively to organizations focused on movement-building might hamper your ability to evangelize for effective altruism—people would quite justifiably be suspicious of an effective altruism movement that was too focused on movement-building.

Similarly, from the point of view of the movement as a whole, people's justifiable suspicions of an EA movement too focused on movement building might lead to such a movement growing more slowly than an EA movement that was less focused on movement building.

On why those suspicions on 1 and 2 are justified: even if an EA movement that was very focused on movement-building grew faster than one less focused on movement building, it could easily grow into the wrong kind of movement—one only good at self-promotion, not doing object-level useful things.

Concrete successes by EA-backed charities may itself be very valuable for helping build the EA movement.

How much money to spend on movement building depends a lot on room for funding.

Let's say you run a local EA meetup. If you have trouble finding a good room for the meetup, spending money on the room might be very useful.
Spending the money to advertise the meetup on meetup.com is also going to have a very good return.

Also, another consideration you haven't mentioned is the belief that focusing on improving the "product of EA" (e.g., quality of research, etc.) is better for movement building purposes than outright outreach. For example, Paul Christiano:

Sometimes “movement-building” is offered as an example of an activity with very high rates of returns. At the moment I am somewhat skeptical of these claims, and my suspicion is that it is more important for the “effective altruism” movement to have a fundamentally good product and to generally have our act together than for it to grow more rapidly, and I think one could also give a strong justification for prioritization research even if you were primarily interested in movement-building. But that is a much longer discussion.

for example, can we trust 80,000 Hours' estimates of the multiplier on giving to Give Well and GWWC? Might other organizations (such as the Centre for Effective Altruism, which is behind 80,000 Hours) be more effective at movement-building?

I'm pretty sure that 80K believes that a donation to CEA is the best for movement building.